Accurate information on the incidence, causes, social, and economic consequences of work-related conditions in older workers is essential to guide public policy. Specific information is needed on effective methods of rehabilitation and re-injury prevention for this segment of the workforce. Unfortunately, little is known about these issues. Our pilot investigation and other studies suggest significant differences between older and younger workers' experience related to occupational injuries and illness. As the number of workers over age 55 will be growing at a rate that is at least twice that of the general workforce, this area will become more important. We propose a prospective, population-based study of long-term outcomes in older workers with occupationally-related conditions, building on a multifactorial model of influences on outcomes. State law requires notification by employers to the New Hampshire State Department of Labor (NHDOL) of any work-related condition reported by an employee. Using this data, workers over age 55 will be contacted 2-6 weeks after an occupational injury or illness occurs. They will complete a mailed baseline questionnaire, with prospective follow-up at 3 and 9 months post initial questionnaire. A comparison younger worker with similar affected body part and gender will be selected for each case. Assuming at least a 65% participation rate (based on our prior pilot study), we will be able to recruit a final sample of over 1000 workers over age 55 and at least as many comparison cases over 6 months. The prospective design will enable us to evaluate causal relationships and avoid recall bias. We have tested the proposed methods for subject recruitment and most of the survey domains and content. With this large cohort, we can develop precise estimates and examine specific subgroups such as those in high-risk industries, with particular types of injuries or who have chronic health conditions. Specific hypotheses can be tested, and a variety of research questions can be answered.